Mixing device



Sept. 24, 1963 E. M. KANE MIXING DEVICE Filed Sept. 6. 1960 INVENTOR ERNEST M. KANE A TTOR/VE Y because of other design problems.

United States Patent 3,104,867 MEXING DEVKZE Ernest M. Kane, 1%63 Valiey Park Brivc, Oxnard, Calif. Filed Sept. 6, 1969, Ser. No. 54,330 6 Claims. (tit. fis -3d) (Granted under Titie 35, US. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to a remotely-operated device for mixing material and more particularly to a device for mixing material in a wet powdered state. An example of such a material is an explosive or pyrotechnic composition consisting of powdered metal, powdered oxidizing material, and a liquid such as monomeric styrene which will be polymerized in a later operation.

One of the most critical problems confronting designers of mixing devices for explosive materials has been to develop a simple device which can be remotely operated to efliciently obtain a homogeneous mixture of an explosive material and then remotely unload the material with a reasonable degree of safety. Moreover, there has been a need in the art for a simple explosive material mixing device which can be operated remotely to make a change from a mixing operation to an unloading operation without having any of the rotating or moving parts of the device coming into contact with one another. For safety reasons it is necessary that parts of a mixing device not come into frictional contact during the mixing or unloading of an explosive material since any such contact could easily provide sufiicient heat to ignite the explosive. In cases where the percentage of liquid is less than the amount required to render the mass semi-fluid, additional problems are presented by the formation of lumps, and by the tendency of the material to adhere to internal corners of the mixing vessel, thus avoiding the mixing action. Several devices which are presently prevalent for mixing explosive material are (l) the well- Eknown paddle wheel mixer and (2) the mixer employing rotating mullers in a mixing pan. In both of these devices the mixture must be essentially semi-fluid in order to obtain satisfactory mixing. Since the chemically d sirable proportion of liquid to solid ingredients is often too dry, a volatile solvent is often added in order to achieve this semi-fluid consistency. V This practice is undesirable because of the fire and toxicity hazards introduced, and because undesirable chemical reactions may result. Another disadvantage is that the mixer must be kept in motion until the solvent has substantially evaporated in order to assure a uniform mixture. In addition to the above problems, these mixers cannot be operated remotely for performing both the mixing operation and the unloading operation with any degree of safety. Present unloading techniques have been to tilt the mixing pan or provide a removable plug in the bottom of the mixing pan. The first technique mentioned is diflicult to carry out because of the difficulty of balanc ing the machine in both loaded and empty positions, and

The second technique is hazardous because of the friction between parts which is inherent in the plug removal. Other devices found in the art of mixing non-explosive materials are unsuitable for safely mixing explosive material by remote operation. One such device investigated is a disc extending within a rotating pan for plowing the material 7 toward the center of the pan when the pan is rotated and upon turning'the disc it will plow the material over the edge of the pan. One of the difiiculties with such a device is that for mixing explosive materials the periphery "ice of the disc must substantially conform and be close, in the order of of an inch, to the inner surface of the mixing pan for proper mixing, and this tolerance is too close to allow turning the disc to an emptying position without lifting the disc up, turning it to the emptying position and then letting it down. These problems and others are overcome in the present invention by providing a disc, the periphery of which is rotatable about a fixed axis and a means for remotely driving the mixing pan first in one direction and then in the opposite direction. Upon rotating the pan in the first direction explosive material in the pan is plowed toward the center of the pan and upon rotating the pan in the opposite direction the explosive material is plowed over an outside edge of the pan. With such a device safety will be inherent since none of the parts of the device come into frictional contact between the mixing and unloading operations. The device is of simple construction even though it is operated remotely, and materials of widely varied consistencies and solid content can be mixed in it.

Further, the disc is provided with vanes on the unloading side 44 of the disc so as to face the flow of a material when the mixing pan rotates in the first direction.

These. vanes rotate the disc when the material is being mixed or unloaded to prevent the material from piling up against the disc and when unloading the vanes further act as cups to carry the material to the outer edge of the mixing pan. Thus a good homogeneous mixture is obtained and the unloading is facilitated. Another feature of the invention is the employment of a mixing pan which consists of an annular trough surrounding a truncated conical center section. This causes the material during mixing to be lifted up and moved toward the center of the pan as it plows against the disc and then dropped after passing the disc. This unique style of mixing produces a homogeneous mixture of the material in a relatively short period of time. It is to be understood that the invention can be employed for mixing any material whether it be a dry mix, a fluid, a semi-fluid, or a wet solid or whether it be an explosive or a nonexplosive material.

An object of the invention is to provide a device which will more etfi-ciently mix a material.

Another object of the present invention is to provide a device which will elfliciently mix and unload material in a wet solid state.

A further object is to provide a simple and safe device for homogeneously mixing and unloading explosive material by remote operation.

A still further object is to provide a device which can be remotely operated to change from a mixing operation to an unloading operation without any of the moving parts of the device frictionally coming into contact with one another.

Other objects and many of the attendantadvantages of this invention will be readily appreciated as the same becomes better understood hy reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a top view of the device.

FIG. 2 is a side View of the device taken along line 11-11 of FIG. 1. a

FIG. 3 is a view taken along line III- 1H of FIG. 1.

Referring now to the-drawings, wherein like reference numerals designate like or corresponding parts throughout the several views, there is shown a mixing pan 10 rotatably mounted by bearings 11 on an axle 12. The pan can be rotated in a counterclockwise or a clockwise direction as seen in FIG. 1 by a remotely-operated reversible-variable-speed motor 14, the driving action of the motor being obtained through the engagement of a pinion gear 16 fixedly attached to the motor 14 with a ring gear 13 which is fixedly attached to the mixing pan 1th A circular disc 19 having a mixing side 2d, an unloading side 21 and vanes 22 is rotatably mounted by bearings 23 on a shaft 24, the shaft 24 being fixedly attached to the axle 12 by a crossbar 26 and laterally offset by the crossbar 26 a (preferably of an inch) from the lower peripheral portion of the disc on both sides of the lowest point 28 so that as seen in a view such as FIG. 3, the inner bottom surface portion 3i) of the pan substantially conforms in shape to the lower peripheral portion of the disc. It is necessary that the lower peripheral portion of the disc and the inner bottom surface portion 3t) of the mixing pan be located in close relationship to one another, preferably & of an inch, for efficient mixing and unloading of the material. A roller 32 is rotatably mounted on a roller shaft 33, the roller shaft being fixedly attached to an .arm 34 which in turn is rotatably mounted on a fixed shaft 35. The arm 34 is stopped in its rotation about the fixed shaft 35 by a stop 37 so that the roller 32 is positioned approximately of an inch from the inner bottom surface portion 3b" of the disc. A lump of material meeting the roller :12 will raise it up, the roller returning to its original position after the passing of the lump. When it is desired to mix .a material the mixing pan is rotated in a counterclockwise direction as seen in FIG. 1, causing the material to be plowed by the disc 19 toward the center of the pan and to be crushed by the roller 32. By having the inner surface bottom portion 3% of the pan substantially conforming to the lower peripheral portion of the disc on an inner side of the lowest point 28, as seen in H6. 3, a sloping surface is configured which will cooperate with the disc to lift the material in the pan up as well as moving it toward the center of the pan as it plows against the mixing side 20 of the disc, the material dropping down again as it passes by the disc. This unique type of mixing action produces ahomogeneous mixture within a relatively short period of time. time both the roller 32 and the disc 19 rotate around their respective shafts by the movement of the material past their surfaces, which rotation makes the roller and the disc self-cleaning and which ensures that the material does not pile up when it meets these surfaces. homogeneous mixture of the material is obtained the mixing pan 10 is remotely rotated in a'clockwise direction causing the material to be plowed against the unloading side 21 of the disc thereby forcing the material over an outer edge 36 of the pan. 4

The vanes '22 on the disc are directed outwardly from respective radials of the disc on the unloading side 21 of the disc and each vane as seen when rotated to a lowest position on the disc is directed substantially parallel to At the same After a a radial of the pan so that each vane as seen at the lowest position is substantially normal to the direction of flow ofthe material passing by the vane. The disc has openings 43, one adjacent each vane, so that during the mixing operation the material will plow against the mixing side 20 of the disc, some of the material passing through the openings 43 to strike the vanes 22 and exert a rotative force component on the disc around the shaft 24. The openings and the vanes extend a substantial portion of a radius of the disc so that substantially any depth of material within the pan will result in the entire flow of the material past the vanes to act on the vanes and impart the desired mixing and unloading action. The openings 43 serve a triple function in that in addition to allowing the material to strike the vanes 22 during mixing (1) the openings relieve any tendency of the material to stagnate against the lower portion of the mixing side of the disc by allowing some of the material to pass through the openings and (2) in passing through the openings the material turns a corner by its impingement on a vane thereby insuring a unique mixing action. The rotation of the disc 19 or the increased rotation thereof during the mixing operation produces a better mixing action on the material in that the material is rotated. away to prevent a piling up against the mixing side 21 of the disc. The vanes 22 of the type described also prevent a piling up of the material against the unloading side of the disc 21 and facilitate unloading the material from the mixing pan it) when the pan is rotated in a clockwise direction. During the unloading operation, when the material is being plowed against the unloading side 21 of the disc 19, the vanes 22 on an inward side 56 at the lower portion of the disc impart a rotative force component to the disc around the shaft 24. At the same time the vanes 22 on .an outwardside 48 of the disc at the lower portion of the disc up to the outer edge'36 of the mixing pan act as cups in carrying thematerial to the outer edge 36 of the pan. Thus, it is seen that the vanes 22 on the disc 19 serve a double function, namely, preventing a piling up of the explosive material against the disc when the mixing pan is either mixing or unloading and cupping the material to carry it to the outer edge 36 during the unloading operation. The construction of the vanes 22 on the disc 19 may be accomplished by striking the vanes out of a plane-surfaced disc to the position v I described above. The ideal power supply for the device 7 is a reversible, variable-speed motor. The variable-speed feature is desirable as a means of preventing any tendency for the mixture to form excessive dust, or any tendency.

to adhere to the truncated conical center section. In the operation of the device a material such as an explosive wet solid including by weight of magnesium and an oxidizer and 10% by weight of a liquid plastic monomer is placed inthe mixing pan 10. The mixing pan is'then rotated in a counterclockwise direction, as seen in'FIG. 1, a

by an operator located at some remote station (not shown). disc 19 toward the center of the mixing pan and the disc will rotate by the action of the explosive material mixture of the explosive material is obtained the operator at the remote station merely changes the direction ofrotation of the mixing pan for the unloading of the explosive material. The explosive material is then plowed bythe unloading side 21 of the disc, the material acting on the J vanes 22 again to rotate the disc. This rotation prevents the material from piling up against the unloading side 21 of the disc and causes the vanes 22 to act as cups tocarry thematerial to the outside edge 36 of the mixing pan into a chute or container (not shown).

It is now apparent that the invention provides a-simplc mixing device which will produce a homogeneous mixture of material with improved efiiciency. This is accomplished by employing vanes on a rotatable disc which will rotate the disc to prevent a pileup of the material against the disc during mixing or unloading and which will further act ascups to carry the material to the outside edge of the pan during unloading. Also, the mix is improved by conforming the inner bottom surface portion of the pan in close relationship to the periphery of the disc so that the material during mixing is plowed inwardly and raised up. upon meeting the plow and then falls down after passing the plow. Further, it is now apparent that the invention provides .a simple device which can be operated remotely for mixing and unloading an explosive material-with a greater degree of safety.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore toa be understood that within The explosivematerial will be plowed by thQ' The material thenv the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim:

1. A device for mixing material comprising a mixing pan rotatably and centrally mounted on a substantially upright axle with an outside edge of the pan circumscribing the axle, said pan having an inner surface, a substantially upright disc mounted for rotation about a fixed axis which is positioned a predetermined distance from a longitudinal axis of the axle, the disc having a periphery which rotates around the fixed axis at a point located therealong, the periphery of the disc defining a plane which lies between a plane radially extending from said longitudinal axis through said point and a plane which is normal to the radially extending plane and which also passes through said point, at least a part of the periphery of the disc extending into the mixing pan and located in close proximity to the pans outer edge, said disc having a lowest point with respect to the inner surface of the mixing pan, at least a portion of the inner surface of the mixing pan conforming to a lower peripheral portion of the disc on both sides of the lowest point of the disc so that the material will be raised up on one side or the other of the pan depending upon the direction of rotation of the pan and means for rotating the mixing pan first in one direction and then in an opposite direction whereby upon rotating the pan in the first direction the disc rotates by action of the material thereon and plows the material toward the center of the pan and upon rotating the pan in an opposite direction the disc rotates in an opposite direction by action of the material thereon and plows the material over the outer edge of the pan.

2. A device as claimed in claim 1 wherein said portion of the inner surface of the pan is equidistant from the lower peripheral portion of the disc on both sides of the lowest point of the disc.

3. A device as claimed in claim 2 .wherein the disc has a mixing side and an unloading side, the unloading side of the disc having vanes near the periphery of the disc, said vanes being directed outwardly from the unloading side of the disc and each of the vanes as seen when rotated to its lowest position on the disc directed toward the outside edge of the pan whereby when the device is unloading the vanes rotate the disc and act as cups to carry the material to the outer edge of the mixing pan.

4. A device as claimed in claim 3 wherein the disc has openings near its periphery, each opening being adjacent a respective vane tor allowing material to pass therethrough and strike the vanes when the device is mixing and each of the vanes as seen when rotated to its lowest position on the disc directed substantially parallel to a radial of the pan whereby the vanes rotate the disc when the device is mixing or unloading and the vanes further act as cups to carry the material to the outer edge of the mixing pan when the device is unloading.

5. A device as claimed in claim 4 wherein the openings and the vanes extend a substantial portion of a radius of the disc so that material of substantially any depth within the pan will act throughout the depth with the openings and the vanes.

6. A device for mixing material comprising a mixing pan rotatably and centrally mounted on a substantially upright axle with an outside edge of the pan circumscribing the axle, said pan having an inner surface, a substantially upright disc mounted for rotation about a fixed axis which is positioned a predetermined distance from a longitudinal axis of the axle, the disc having a periphery which rotates around the fixed axis, at least a part of the periphery of the disc extending into the mixing pan and located in close proximity to the pans outer edge, said disc having a lowest point with respect to the inner surface of the mixing pan, at least a portion of the inner surface of the mixing pan conforming to a lower peripheral portion of the disc on both sides of the lowest point of the disc so that the material will be raised up on one side or the other of the pan depending upon the direction of rotation of the pan, the portion of the inner surface of the pan being equidistant from the lower per-ipheral portion of the disc on both sides of the lowest point of the disc, said disc having a mixing side and an unloading side, the unloading side of the disc having vanes near the periphery of the disc, the vanes being directed outwardly from the unloading side of the disc and each of the vanes as seen when rotated to its lowest position on the disc directed toward the outside edge of the pan and directed parallel to a radial of the pan and said disc having openings near its periphery, each opening being adjacent a respective vane for allowing the material to pass therethrough and strike the vanes when the device is mixing whereby the vanes rotate the disc when the device is mixing or unloading and the vanes further act as cups to carry the material to the outer edge of the mixing pan when the device is unloading.

References Cited in the file of this patent UNITED STATES PATENTS 1,875,794 Zettergren Sept. 6, 1932 2,518,428 McM-urr-ay Aug. 8, 1950 FOREIGN PATENTS 770,083 France Dec. 22, 1930 941,606 Germany Apr. 12, 1956 

1. A DEVICE FOR MIXING MATERIAL COMPRISING A MIXING PAN ROTATABLY AND CENTRALLY MOUNTED ON A SUBSTANTIALLY UPRIGHT AXLE WITH AN OUTSIDE EDGE OF THE PAN CIRCUMSCRIBING THE AXLE, SAID PAN HAVING AN INNER SURFACE, A SUBSTANTIALLY UPRIGHT DISC MOUNTED FOR ROTATION ABOUT A FIXED AXIS WHICH IS POSITIONED A PREDETERMINED DISTANCE FROM A LONGITUDINAL AXIS OF THE AXLE, THE DISC HAVING A PERIPHERY WHICH ROTATES AROUND THE FIXED AXIS AT A POINT LOCATED THEREALONG, THE PERIPHERY OF THE DISC DEFINING A PLANE WHICH LIES BETWEEN A PLANE RADIALLY EXTENDING FROM SAID LONGITUDINAL AXIS THROUGH SAID POINT AND A PLANE WHICH IS NORMAL TO THE RADIALLY EXTENDING PLANE AND WHICH ALSO PASSES THROUGH SAID POINT, AT LEAST A PART OF THE PERIPHERY OF THE DISC EXTENDING INTO THE MIXING PAN AND LOCATED IN CLOSE PROXIMITY TO THE PAN''S OUTER EDGE, SAID DISC HAVING A LOWEST POINT WITH RESPECT TO THE INNER SURFACE OF THE MIXING PAN, AT LEAST A PORTION OF THE INNER SURFACE OF THE MIXING PAN CONFORMING TO A LOWER PERIPHERAL PORTION OF THE DISC ON BOTH SIDES OF THE LOWEST POINT OF THE DISC SO THAT THE MATERIAL WILL BE RAISED UP ON ONE SIDE OR THE OTHER OF THE PAN DEPENDING UPON THE DIRECTION OF ROTATION OF THE PAN AND MEANS FOR ROTATING THE MIXING PAN FIRST IN ONE DIRECTION AND THEN IN AN OPPSOITE DIRECTION WHEREBY UPON ROTATING THE PAN IN THE FIRST DIRECTION THE DISC ROTATES BY ACTION OF THE MATERAIL THEREON AND PLOWS THE MATERIAL TOWARD THE CENTER OF THE PAN AND UPON ROTATING THE PAN IN AN OPPOSITE DIRECTION THE DISC ROTATES IN AN OPPOSITE DIRECTION BY ACTION OF THE MATERIAL THEREON AND PLOWS THE MATERIAL OVER THE OUTER EDGE OF THE PAN. 